Over the past few years of recession and regression, it has become a trite truism of European politics that you can't go wrong going to the right. Politicians across the continent have found a new magic formula for electoral success and survival by playing on fears of foreigners and particularly of Islam – the wink and a nod that says that immigration has been the root of our social and economic decline. This is by no means an exclusively rightwing vice. Anyone who has heard the Dutch Labour party recently will have difficulty putting light between them and the demagogue Geert Wilders.

Until today, they might have tried to argue that there was no harm in it, that it's healthy even, a rebalancing of the scales after two decades of biting our tongues and creeping political correctness.

The French airwaves have been full of such ugly equivocation these past few weeks as Nicolas Sarkozy has lurched his party wildly to the right in an attempt to save his skin, claiming there were "too many immigrants in France" and stoking Islamophobia with a ridiculous claim that the French were being secretly forced to eat halal; his prime minister François Fillon even said Jews and Muslims should put their dietary laws behind them and embrace modernity.

Claude Guéant, the interior minister who took personal control of the investigation, has been the most consistently xenophobic, championing the superiority of European Christian civilisation over lesser cultures who force their women to cover up – yes, observant Jews and Muslims, he meant you. The nadir came last week when Sarkozy's new immigration chief Arno Klarsfeld – the eldest son, ironically, of Nazi-hunter Serge Klarsfeld – called for a wall to be built between Greece and Turkey to save Europe from barbarian invaders.

Today in Toulouse we have been given a horrific illustration of where such delirious cynicism can lead. All of those who have been shot or killed in and around the city in the past eight days have had one thing in common. They are from visible minorities. They had names or faces that marked them out as not being descended, as Jean-Marie Le Pen would say, from "our ancestors the Gauls". Their roots – both Jewish and Muslim – were in the Maghreb or the Caribbean. They were, in short, a snapshot of la France metissée – the mixed race, immigrant France that works hard and "gets up early" to empty bins and look after children; the people who die disproportionately for France yet who are also most often locked up in its prisons and crumbling banlieues.

As one father said this morning as he hugged his son to him outside the school, "They are attacking us because we are different."

Police are a long way yet from catching, never mind understanding, what was going through the head of someone who could catch a little girl by the hair so he wouldn't have to waste a second bullet on her. But some things are already becoming clear. He shouted no jihadist or anti-Semitic slogans, going about his grisly business in the cold, military manner oddly similar to Anders Behring Breivik, the Norwegian gunman who massacred 77 people at a social democrats summer camp last summer.

As with Breivik, politicians will be quick to the thesis of the lone madman. Another lone madman influenced by nothing but his own distorted mind, like the lone gang of neo-Nazis who had been quietly killing Turks and Greeks in Germany for years unbothered by the police, who preferred to put the murders down to feuds or honour killings.

What could be the link, they ask, between Jewish children and French military personnel? The link is they are both seen – and not just by a far-right fringe – as symbols of all that has sabotaged la France forte, to borrow Sarkozy's election slogan. Confessional schools, be they Jewish or an informal weekend madrassa, are seen as actively undermining the secular Republic by activists of groups like the Bloc Identitaire and the Front National, as well as some members of Sarkozy's UMP, and even some on the left.

A black man or a Muslim, particularly one of Algerian origin, in a paratrooper's uniform touches a raw nerve among the old guard of the far right. It was the paratroopers who did the bulk of the dirty work to keep Algeria French, and who also tried to oust De Gaulle when he went against them.

Today is the 50th anniversary of the end of that war that left more than a million dead and two countries twisted and contorted by the pain of it in almost equal and opposite ways.

Not even Sarkozy, who has most politically to lose from these killings, is trying to hide the link with race and religion. Just as he echoed the old National Front slogan "Love France or leave it" and then denied he ever said it, he yesterday called on the French people to stand up "against hate", having spent the past few months manically stirring it. The next 34 days will see whether he will be swept away by the storm he has helped to start.